We know that anyone born of God does not continue to sin; the One who was born of God keeps them safe, and the evil one cannot harm them.
“We know that anyone born of God does not continue to sin” It does not mean that a Christian will be sinless, but that he will not live a lifestyle of sin, as before his rebirth [salvation] to Christ.
“the One who was born of God keeps them safe” A Christian’s salvation is secured in the hands of Jesus Christ and will never lose it, according to John 10:28-29 which says, “28 I give them eternal life, and they shall never perish; no one will snatch them out of my hand. 29 My Father, who has given them to me, is greater than all; no one can snatch them out of my Father’s hand.”
“the evil one cannot harm them” The word “harm” suggests the destruction of their faith in Jesus Christ. Jesus is the author and finisher of our faith and will strengthen us to endure the attacks of the demonic forces of evil without losing our faith in Him.